The Experts below are selected from a list of 156 Experts worldwide ranked by ideXlab platform
Jian Cao - One of the best experts on this subject based on the ideXlab platform.
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thermomechanical analysis of an electrically assisted wire drawing process
Journal of Manufacturing Science and Engineering-transactions of The Asme, 2017Co-Authors: Antonio Sanchez J Egea, Hernan Alberto Gonzalez Rojas, Diego J Celentano, Jordi Jorba Perio, Jian CaoAbstract:Electrically-assisted wire drawing process is a hybrid manufacturing process characterized by enhancement of the Formability, ductility and elongation of the wire drawn specimen. A thermomechanical model to describe the change of the mechanical response due to the thermal contribution is proposed in this work. Additionally, a numerical simulation was conducted to study the potential and limitations of this hybrid process by using two different hardening laws: a phenomenological and a dislocationbased hardening laws. The results show how the flow stress, the effective plastic strain and residual stresses behave under the electroplusing effect. In addition, Electron Backscattered Diffraction was used to study the electropulsing treatments on the microstructure during cold drawing. It is observed a decrease of the high and low angle grain boundaries for samples deformed with electropulsing. This detwinning process has a strong influence on the strain hardening by improving the Material Formability. It was shown that the two proposed hardening laws adequately describe the electrically-assisted wire drawing process showing a similar mechanical behavior. Nevertheless, the dislocation-based hardening law has the potential to be generalized to many other Material and process configurations without extensive number of Material tests as the phenomenological hardening law would require.
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effective forming strategy for double sided incremental forming considering in plane curvature and tool direction
Cirp Annals-manufacturing Technology, 2016Co-Authors: Newell Moser, J. Chen, Zixuan Zhang, Huaqing Ren, Huan Zhang, Yi Shi, Ebot Ndipagbor, Kornel F Ehmann, Jian CaoAbstract:Abstract The success of a toolpath in double-sided incremental forming (DSIF) is strongly related to the specified tool gap. It is hypothesized in this work that maintained contact between tools and the sheet can improve the distribution of sheet thickness and hence, improve Material Formability and prevent premature fracture. Simulation and experimental studies reveal that thickness prediction models solely dependent on the local wall angle are inadequate for general part geometries. A ‘Shamrock’ geometry is proposed leading to the development of a novel improved thickness correction model that incorporates wall angle, in-plane curvature, and tool direction.
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a comparative study on process potentials for frictional stir and electric hot assisted incremental sheet forming
Procedia Engineering, 2014Co-Authors: Tingting Cao, Hui Long, J. Chen, Jian CaoAbstract:Abstract Incremental sheet forming (ISF), as an advanced forming technique, has received increasing interest from both academia and industry due to its improved Formability, greater process flexibility and reduced energy consumption in its life cycle. However, with the growing application of lightweight alloys with very limited Material elongation, conventional ISF inevitably encounters challenges in processing these alloys at room temperature, especially in forming magnesium and titanium alloys. Therefore, heat-assisted ISF techniques have been proposed to further enhance Material Formability at elevated temperatures. In this work, two heat-assisted ISF approaches, frictional stir- and electric hot- assisted ISF, have been employed to process the hard-to-form Materials in terms of the flexibility and local dynamic heating. The temperature evolution and corresponding forming force at different feed rates of these two techniques, is investigated in detail to build up a processing window. In addition, process capabilities are compared by forming different geometrical shapes of magnesium alloy AZ31B of 1.4 mm sheet thickness. The investigation results show the pros and cons of frictional stir- and electric hot- assisted ISF. Frictional stir-assisted ISF is more efficient than electric hot-assisted ISF under current experimental results. However, electric hot-assisted ISF has faster heating rate which makes this technique less dependent on the component geometry.
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mechanism investigation for the influence of tool rotation and laser surface texturing lst on Formability in single point incremental forming
International Journal of Machine Tools & Manufacture, 2013Co-Authors: Weichao Wu, Dongkai Xu, Bin Lu, Rajiv Malhotra, J. Chen, Jian CaoAbstract:Abstract Single point incremental forming (SPIF) is a new sheet metal forming process which achieves higher Formability, greater process flexibility and reduced forming force compared to conventional sheet forming operations due to its characteristic of localized deformation. In recent years, a novel SPIF process assisted by localized friction heat is developed to further improve the Material Formability. Physically, the frictional heat is generated by the high relative motion at tool–workpiece interface resulted from tool rotation. However, the mechanisms behind Formability difference induced by tool rotation at both low and high speed ranges are required to investigate in detail. In this paper, a series of experiments with an increase of tool rotation speeds ranging from 0 to 7000 rpm are conducted to form AA5052-H32 aluminum alloy sheets into a truncated funnel. Additionally, the obtained results are analyzed in terms of Formability, forming forces and temperature trends to find out the different roles of friction and heat during the forming process. As a result, the Formability behaviors at varying tool rotation speeds can be categorized into four stages according to different reasons. It indicates that friction is the dominant factor in low tool rotation speed range (0–1000 rpm) but will be substituted by thermal effect and potential dynamic recrystallization in high tool rotation speed range (2000–7000 rpm). Furthermore, due to the proved lubrication enhancement and hydrodynamic enhancement generated by surface textures, a laser surface textured forming tool is also utilized to show its influence on forming forces, measured temperatures and the corresponding Formability. Finally, it demonstrates that the fabricated laser surface texturing (LST) is capable to reduce the friction at tool–workpiece interface and change the magnitude of heat generation.
Hui Long - One of the best experts on this subject based on the ideXlab platform.
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Investigating Formability enhancement in double side incremental forming by developing a new test method of tension under cyclic bending and compression
Journal of Materials Processing Technology, 2020Co-Authors: Rui Dai, Hui LongAbstract:Abstract Incremental sheet forming (ISF), including single point incremental forming (SPIF) and double side incremental forming (DSIF), has demonstrated significantly enhanced Material Formability compared to traditional sheet metal forming processes. However, the Material deformation mechanisms that lead to the enhanced Formability in DSIF are not fully understood. In this study, a new test method, named as Tension under Cyclic Bending and Compression (TCBC), has been developed to investigate four deformation modes observed in DSIF, including tension, compression, bending and cyclic loading, on the Material Formability enhancement. An analytical model based on the elementary plasticity theory has been developed to characterize the effect of tension, compression, bending and cyclic loading on the initiation of Material plastic deformation. A TCBC rig has been manufactured and experimental tests of two aluminium alloys have been conducted by applying the Design of the Experiments to investigate the significant effects of different deformation modes on the Material Formability. Finite element modelling of TCBC test as well as DSIF process has also been developed to compare their plastic strain evolution and strain paths during the cyclic deformation process. The Material Formability has been found to be improved significantly under TCBC condition and the existence of compression loading leads to strengthened localized Material plastic deformation, which contributes to the enhanced Material Formability and delayed fracture. The new TCBC test method developed in this study has demonstrated its potential to replace the current testing method using the DSIF process itself for Material Formability studies.
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A review on Material fracture mechanism in incremental sheet forming
The International Journal of Advanced Manufacturing Technology, 2019Co-Authors: Sheng Ai, Hui LongAbstract:In incremental sheet forming (ISF), including single point incremental forming (SPIF) and double side incremental forming (DSIF), the Material Formability can be significantly enhanced when compared with conventional sheet forming processes. The Material deformation in ISF is far more complicated because of the combined Material deformation under stretching, bending, shearing, and cyclic loading, with an additional effect of compression in DSIF. Despite extensive investigation on Material deformation during ISF, no theory has yet been widely agreed to explain different types of the Material fracture behavior observed in ISF experiments. This paper presents a comprehensive review on the Formability enhancement in ISF and proposes possible fracture mechanisms explaining the different types of fracture behavior observed in the experimental investigations. Discussions are presented to outline the current research progress and possible solutions to overcome the current ISF process limitations because of the Material processing failure due to fracture.
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a comparative study on process potentials for frictional stir and electric hot assisted incremental sheet forming
Procedia Engineering, 2014Co-Authors: Tingting Cao, Hui Long, J. Chen, Jian CaoAbstract:Abstract Incremental sheet forming (ISF), as an advanced forming technique, has received increasing interest from both academia and industry due to its improved Formability, greater process flexibility and reduced energy consumption in its life cycle. However, with the growing application of lightweight alloys with very limited Material elongation, conventional ISF inevitably encounters challenges in processing these alloys at room temperature, especially in forming magnesium and titanium alloys. Therefore, heat-assisted ISF techniques have been proposed to further enhance Material Formability at elevated temperatures. In this work, two heat-assisted ISF approaches, frictional stir- and electric hot- assisted ISF, have been employed to process the hard-to-form Materials in terms of the flexibility and local dynamic heating. The temperature evolution and corresponding forming force at different feed rates of these two techniques, is investigated in detail to build up a processing window. In addition, process capabilities are compared by forming different geometrical shapes of magnesium alloy AZ31B of 1.4 mm sheet thickness. The investigation results show the pros and cons of frictional stir- and electric hot- assisted ISF. Frictional stir-assisted ISF is more efficient than electric hot-assisted ISF under current experimental results. However, electric hot-assisted ISF has faster heating rate which makes this technique less dependent on the component geometry.
Giuseppina Ambrogio - One of the best experts on this subject based on the ideXlab platform.
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analysis of the thickness distribution varying tool trajectory in single point incremental forming
Proceedings of the Institution of Mechanical Engineers Part B: Journal of Engineering Manufacture, 2011Co-Authors: L Manco, L Filice, Giuseppina AmbrogioAbstract:Single-point incremental forming (SPIF) presents a great competitive advantage with respect to the conventional stamping processes, in particular when small batches have to be produced. The competitiveness of such a process cannot be evaluated only by comparison with other traditional manufacturing processes. It is clear that the process allows metal forming in the critical ‘necking-to-tearing’ zone and this results in a strong thinning before failure if the process is well designed. What is more, the process is complex because of the number of variables involved. Thus, it is not possible to consider that the process has been well assessed; several aspects remain that must be clarified. In this paper a wide-ranging investigation of tool trajectory selection versus Material Formability is presented. In particular, although the same shape has to be manufactured, it is possible to select a particular trajectory among the many possible ones; this choice will affect the final thickness distribution and formabi...
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application of incremental forming process for high customised medical product manufacturing
Journal of Materials Processing Technology, 2005Co-Authors: Giuseppina Ambrogio, L De Napoli, L Filice, Francesco Gagliardi, Maurizio MuzzupappaAbstract:Abstract Incremental Forming processes have been introduced in the recent past as an alternative to the money consuming stamping technology, when small batches have to be manufactured. Anyway, they introduce some advantages in terms of flexibility and Material Formability but, also, some problems such as the dimensional accuracy decreasing. In this paper, a particular application is carried out taking into account the development of an innovative technique to produce a customised ankle support. In this way Incremental Forming process has been selected for the sheet profiling, exalting the role that this technology may play when single complex product has to be manufactured. The producing procedure finishes with a measure of the dimensional accuracy that shown a good result for the desired application.
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influence of some relevant process parameters on the dimensional accuracy in incremental forming a numerical and experimental investigation
Journal of Materials Processing Technology, 2004Co-Authors: Giuseppina Ambrogio, Livan Fratini, L De Napoli, L Filice, I Costantino, Maurizio MuzzupappaAbstract:Abstract As known, incremental forming is a flexible and innovative sheet metal forming process which allows complex shape shells forming without the need for any die. For these reasons, incremental forming is nowadays suggested for rapid prototyping and customised products. The present paper is focused on Material Formability in incremental forming and, in particular, on the evaluation and compensation of elastic springback. The latter significantly modifies the imposed shape. For this purpose, a deeper assessment of the process was developed following three different approaches. First of all, a wide experimental investigation on the influence of some relevant process parameters was developed. At the same time, an explicit FEM analysis of incremental forming process was carried out in order to verify its effectiveness and, as a consequence, its ability to be used as a design tool. Furthermore, the obtained parts were analysed by a reverse engineering technique and the measured geometry was numerically compared with the desired one, with the aim to quantify the geometrical discrepancies. In this way, an integrated numerical/experimental procedure is proposed in order to limit the shape defects between the obtained geometry and the desired one.
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influence of mechanical properties of the sheet Material on Formability in single point incremental forming
CIRP Annals, 2004Co-Authors: Livan Fratini, Giuseppina Ambrogio, L Filice, R Di Lorenzo, F MicariAbstract:Abstract New trends in sheet metal forming are rapidly developing and several new forming processes have been proposed to accomplish the goals of flexibility and cost reduction. Among them single point incremental forming operations, in which the final shape of the component is obtained by the relative movement of a simple and small punch with respect to the blank, appear quite promising. In the paper, Material Formability issues in incremental forming were studied. Some relevant correlations among Material Formability and other mechanical properties of the Material were analysed. The FLD 0 value, i.e. the major strain at fracture in plane strain conditions, was determined for different Materials and the influence of the main Material parameters on Formability was accurately investigated through a statistical analysis.
J. Chen - One of the best experts on this subject based on the ideXlab platform.
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Forming limit evaluation by considering through-thickness normal stress: Theory and modeling
International Journal of Mechanical Sciences, 2019Co-Authors: Qi Hu, Xifeng Li, J. ChenAbstract:Abstract For hydroforming process and incremental forming, the plane stress assumption would be invalid to predict Material Formability. To consider the influence of normal stress on the forming limit strains, the instability perturbation approach proposed by Hu et al. is extended with normal stress. The M–K model with normal stress is chosen to compare with perturbation approach by implementing Hill’48 and Yld2000-2d yield criteria and swift and modified voce hardening laws. To guarantee the convergence of solving process in M–K model with normal stress, the modified increment method is implemented into it. Through comparing the experimental forming limit strains of AA5754-O under plane stress state and the corresponding theoretical values predicted by perturbation approach and M–K model, the suitable yield criterion and hardening law for these two methods are determined. The influences of through-thickness normal stress on the predicted forming limit strains under different stress states are investigated. The results show that forming limit curves (FLCs) in both forms of traditional Forming Limit Diagram (FLD) and equivalent plastic strain (EPS) based FLD (epFLD) enhance with increasing through-thickness normal stress under linear and nonlinear strain paths. The sensitivity of FLD to normal stress is related to the hardening law and the range of strain path in FLD is determined by the yield criterion.
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effective forming strategy for double sided incremental forming considering in plane curvature and tool direction
Cirp Annals-manufacturing Technology, 2016Co-Authors: Newell Moser, J. Chen, Zixuan Zhang, Huaqing Ren, Huan Zhang, Yi Shi, Ebot Ndipagbor, Kornel F Ehmann, Jian CaoAbstract:Abstract The success of a toolpath in double-sided incremental forming (DSIF) is strongly related to the specified tool gap. It is hypothesized in this work that maintained contact between tools and the sheet can improve the distribution of sheet thickness and hence, improve Material Formability and prevent premature fracture. Simulation and experimental studies reveal that thickness prediction models solely dependent on the local wall angle are inadequate for general part geometries. A ‘Shamrock’ geometry is proposed leading to the development of a novel improved thickness correction model that incorporates wall angle, in-plane curvature, and tool direction.
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a comparative study on process potentials for frictional stir and electric hot assisted incremental sheet forming
Procedia Engineering, 2014Co-Authors: Tingting Cao, Hui Long, J. Chen, Jian CaoAbstract:Abstract Incremental sheet forming (ISF), as an advanced forming technique, has received increasing interest from both academia and industry due to its improved Formability, greater process flexibility and reduced energy consumption in its life cycle. However, with the growing application of lightweight alloys with very limited Material elongation, conventional ISF inevitably encounters challenges in processing these alloys at room temperature, especially in forming magnesium and titanium alloys. Therefore, heat-assisted ISF techniques have been proposed to further enhance Material Formability at elevated temperatures. In this work, two heat-assisted ISF approaches, frictional stir- and electric hot- assisted ISF, have been employed to process the hard-to-form Materials in terms of the flexibility and local dynamic heating. The temperature evolution and corresponding forming force at different feed rates of these two techniques, is investigated in detail to build up a processing window. In addition, process capabilities are compared by forming different geometrical shapes of magnesium alloy AZ31B of 1.4 mm sheet thickness. The investigation results show the pros and cons of frictional stir- and electric hot- assisted ISF. Frictional stir-assisted ISF is more efficient than electric hot-assisted ISF under current experimental results. However, electric hot-assisted ISF has faster heating rate which makes this technique less dependent on the component geometry.
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mechanism investigation for the influence of tool rotation and laser surface texturing lst on Formability in single point incremental forming
International Journal of Machine Tools & Manufacture, 2013Co-Authors: Weichao Wu, Dongkai Xu, Bin Lu, Rajiv Malhotra, J. Chen, Jian CaoAbstract:Abstract Single point incremental forming (SPIF) is a new sheet metal forming process which achieves higher Formability, greater process flexibility and reduced forming force compared to conventional sheet forming operations due to its characteristic of localized deformation. In recent years, a novel SPIF process assisted by localized friction heat is developed to further improve the Material Formability. Physically, the frictional heat is generated by the high relative motion at tool–workpiece interface resulted from tool rotation. However, the mechanisms behind Formability difference induced by tool rotation at both low and high speed ranges are required to investigate in detail. In this paper, a series of experiments with an increase of tool rotation speeds ranging from 0 to 7000 rpm are conducted to form AA5052-H32 aluminum alloy sheets into a truncated funnel. Additionally, the obtained results are analyzed in terms of Formability, forming forces and temperature trends to find out the different roles of friction and heat during the forming process. As a result, the Formability behaviors at varying tool rotation speeds can be categorized into four stages according to different reasons. It indicates that friction is the dominant factor in low tool rotation speed range (0–1000 rpm) but will be substituted by thermal effect and potential dynamic recrystallization in high tool rotation speed range (2000–7000 rpm). Furthermore, due to the proved lubrication enhancement and hydrodynamic enhancement generated by surface textures, a laser surface textured forming tool is also utilized to show its influence on forming forces, measured temperatures and the corresponding Formability. Finally, it demonstrates that the fabricated laser surface texturing (LST) is capable to reduce the friction at tool–workpiece interface and change the magnitude of heat generation.
Maurizio Muzzupappa - One of the best experts on this subject based on the ideXlab platform.
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application of incremental forming process for high customised medical product manufacturing
Journal of Materials Processing Technology, 2005Co-Authors: Giuseppina Ambrogio, L De Napoli, L Filice, Francesco Gagliardi, Maurizio MuzzupappaAbstract:Abstract Incremental Forming processes have been introduced in the recent past as an alternative to the money consuming stamping technology, when small batches have to be manufactured. Anyway, they introduce some advantages in terms of flexibility and Material Formability but, also, some problems such as the dimensional accuracy decreasing. In this paper, a particular application is carried out taking into account the development of an innovative technique to produce a customised ankle support. In this way Incremental Forming process has been selected for the sheet profiling, exalting the role that this technology may play when single complex product has to be manufactured. The producing procedure finishes with a measure of the dimensional accuracy that shown a good result for the desired application.
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influence of some relevant process parameters on the dimensional accuracy in incremental forming a numerical and experimental investigation
Journal of Materials Processing Technology, 2004Co-Authors: Giuseppina Ambrogio, Livan Fratini, L De Napoli, L Filice, I Costantino, Maurizio MuzzupappaAbstract:Abstract As known, incremental forming is a flexible and innovative sheet metal forming process which allows complex shape shells forming without the need for any die. For these reasons, incremental forming is nowadays suggested for rapid prototyping and customised products. The present paper is focused on Material Formability in incremental forming and, in particular, on the evaluation and compensation of elastic springback. The latter significantly modifies the imposed shape. For this purpose, a deeper assessment of the process was developed following three different approaches. First of all, a wide experimental investigation on the influence of some relevant process parameters was developed. At the same time, an explicit FEM analysis of incremental forming process was carried out in order to verify its effectiveness and, as a consequence, its ability to be used as a design tool. Furthermore, the obtained parts were analysed by a reverse engineering technique and the measured geometry was numerically compared with the desired one, with the aim to quantify the geometrical discrepancies. In this way, an integrated numerical/experimental procedure is proposed in order to limit the shape defects between the obtained geometry and the desired one.